Alignment apparatus for source of ions



Sept. 20, 1955 B. A. PETERS ET AL ALIGNMENT APPARATUS FOR SOURCE OF IONS Filed Aug. 2, 1954 1 I l l l i l {/6 l/ I l 1 l I ION SOURCE HERME TIC SEA L INVENTORS Be/don A. James A Pe fers, Rickard,

ATT R ALIGNMENT APPARATUS FOR SOURCE OF ICNS Application August 2, 1 954,'Serial No. 447,152 6 Claims. (Cl. 250-413) The present invention is directed to apparatus for aligning an ion source with apparatus utilizingions. More particularly, the invention is directed to an alignment apparatus for aligning an ion source along the axis of the ion path. In its more specific aspects, the invention has to do with apparatus for aligning an ion source with a mass spectrometer. 7

The present invention may be briefly described as an alignment apparatus for a source of ions which comprises, in combination, a first tubular member adapted to pro ect within a pressure reducing means to define a path for mm which is in fluid communication with the pressure reducing means. The first tubular member is provided with at least one slot adjacent its free end in the pressure reducing means. A second tubular member is coaxially arranged in the first tubular member for movement longitudinally in the first tubular member. The second tubular member is adapted to support the source of ions and the second tubular member is provided with means protruding into the slot for resisting rotational movement. Means are operatively connected to the second tubular member for moving the second tubular member along the axis of the ion path. 1 a

The pressure reducing means is suitably a vacuum pump provided with a housing whichencloses the tubular members.

The means for moving the second tubular member may comprise a ring gear threadably attached to the second tubular member which meshes with a pinion which 1s operated from the exterior of the vacuum pump housing either manually or by power means.

The invention will be further illustrated by reference to the drawing in which the single figure illustrates a preferred embodiment.

Referring now to the drawing, numeral 11 designate a vacuum pump housing having a tubular member 12 sealed therewith and projecting with its free end 13 into the vacuum pump housing.

The tubular member 12 is provided with a plurality of lateral ports 14 which fluidly communicate with the vacuum pump housing to provide a path of flow 15 for the ion beams which originate from an ion source 16 shown in dotted lines. This ion source may be any suitable ion source and may comprise means for ionizing the solid, liquid, or gas sample (such as by electron or ion bombardment, by sparking, arcing, etc.), accelerating potentials to withdraw the ions from interior regions of the source, and suitably spaced and insulated slotted plates which may serve the double function of physically aligning and collimating the ion beam and electrically focusing, bending and accelerating the ion beam. The ion source 16 is adapted to rest on a second tubular member 17 which has an annular shoulder 18 and has a slit 19 for the ions to enter the path 15 which is further defined by the second tubular member 17.

The free end 13 of the first tubular member 12 is provided with a slot 20 into which are arranged pins or pro- United States Patent jections 21 which are rigidly connected to the second tubular member 17.

Threadably connected to the first tubular member 12 by mating threads 22 is a ring gear 23 which is provided with recesses 24 to receive the pins 21. The pins 21 are held into the recesses 24 by an annular member 25 which in turn is held in the ring gear 23 by screws 26.

The gear 23 is engaged meshingly with a pinion 27, the free end 28 of pinion 27 protrudes by way of seal 29 through the vacuum pump housing 11. a

In accordance with the present invention, the ion beam which originates with ion source 16 and travels through the slit 19 into the path 15 may suitably be directed into a mass spectrometer or suitable particle accelerators, such as Van de Graaf accelerators and the like. The ion beam may suitably be directed into other apparatus such as mass spectrometer leak detectors which utilize ions.

. Thesealing means 29 may suitably comprise a hermetic arrangement, to insure a vacuum-tight seal on passage of the member 28 through the housing 11. The hermetic bellows arrangement 29 is described in U. S. Patent 2,419,074, issued April 15, 1947, to F. D. Herbert, Jr. It will be preferred to usethe hermetic bellows design, such as illustrated, although other sealing means may be used.

It is not infrequently desirable to move an ion source during operation of a mass spectrometer, and the like. When this is done, the ion source must be properly aligned with the mass spectrometer in three dimensions. In addition, the ion source must be positioned with the mass spectrometer in regard to rotation. Even after a different alignment has been had initially, it is often advantageous to change the .position of the ion source in one dimension along the axis of the ion path. This has been ditficult heretofore. In accordance with the present invention, the best position is determined and the ion source moved to the position. 'However, it is sometimes desirable to change the position if and when it becomes necessary to replace one ion source with another ion source or to change the position for the mass of the ion. Likewise, the ion source position is sometimes changed to compensate for contamination.

In accordance with the present invention, the alignment apparatus may allow this adjustment along the path of the ion beam by moving the member 28 which causes rotation of the ring gear 23 and, therefore, moves the tubular member 17 along the longitudinal axis of the ion beam. Thus the pins resist the rotation of the tubular member 17 and allow the tubular member 17 to be moved from the position shown in the drawing to a second position along the direction of the arrows, indicating the degree of adjustment.

The present invention is quite advantageous in that the supporting structure for the ion source is kept a substantial distance away from the high voltages employed in the upper parts of the ion source which is illustrated diagrammatically. Furthermore, the supporting structure is kept away from the electrical leads which are connected with the ion source. These advantages inure to the present invention besides the advantage of having a positive mechanical adjustment for an ion source which is quite useful in mass spectroscopy.

It will be seen from the foregoing description that the invention is of considerable utility and will lead to more precise adjustments of instruments utilizing ion source than has been possible heretofore.

The nature and objects of the present invention having been completely described and illustrated, what we wish to claim as new and useful and to secure by Letters Patent is:

1. Alignment apparatus for a source of ions which comprises, in combination, a first tubular member adapted Patented Sept. 20, 1955v to project within a pressure reducing means to define a pathfor saidions influid communicationwith saidpres-- sure reducing means, said first: tubular member being provided with at least one slot adjacent its. free end in said. "reducing means, asecond tubular member-"co axially arranged in said first tubular member for movement longitudinally in said first tubular memberand adapted to support said source of ions, said second tubul'ar'rnemb'er being provided with means protruding into slot for resisting rotationalrmovement, and means, operatively connected to said second tubular member for rrrovi'ng said second tubular'memberalon'g the axis-of said ion path;

2. Alignment apparatus for a source of ions which' comprises, in combination; afirst tubular member adapted to project within" a pressure reducing means to define a path for said ions in fluid communication with said pressure reducing" means, said first tubular member being provided with at least one slot adjacent its free end in said pressure reducing: means, a' second tubular member coaxially'arranged in said first tubular member for longitudinal movement insaid first tubular member, said second tubular member having at least one pin arranged in said slot for resisting rotational movement of said second tubular member and being adapted to support said source of ions, and means operatively connected to said second tubular member for moving said second tubular member along thea'xis of said ion path.

3. Alignment apparatus for a source of ions which comprises, in combination, pressure reducing means, a first tubular member arranged to project within said pressure reducing means to define a path for said ions provided with at least one port in fluid communication with said pressure reducing means, said first tubular member being provided with at least one slot adjacent its free end in said pressure reducing means, a second tubular member coaxiall'y arranged in said first tubular member for longitudinal movement in said first tubular member, said sccond'tubular member having at least one pin arranged in said slot for resisting rotational movement of said second tubular member, said second tubular member being adapted to support said source of ions, and means operatively connected to said second tubular member for moving said'second tubular member along the axis of said ion path.

' comprises, in combination, a vacuumpump housing, a

4. Alignment apparatus for a source of ions which comprises, in combination, pressure reducing means, a first tubular member arranged to project within said pressure reducing means to define a path for said ions provided with a plurality of lateral ports in fluid communication with said pressure reducing means, said first tubular member being provided with at least one slot adjacent its free end in said pressure reducing means, a second tubular member coaxially arranged in said first tubular member for longitudinal movement in said first tubular member, said second tubular member having at least one pin arranged in said slot for resisting rotatational movement of said second tubular member, said second tubular member being adapted to support said source of ions, gear means operatively connected to said second tubular member for moving said second tubular member along the axis of said ion path, and power means operatively connected to said gear means projecting outside said pressure reducing means.

5'. Apparatus in accordance with claim 4 in which the pressure reducing means is avacuum pump enclosing said tubular members.

6. Alignment apparatus for a source of ions which first tubular member arranged to project withinsaid vacuum pump'housingtodefine a path for said ions provided with a plurality oflateralports influid-communication with said pressure reducing means, said first tubular member being provided with at least one slot adjacent its free end in said pressure reducing means, a second tubular member coaxially arranged in said first tubular member for longitudinal movement in said first tubular member, said secondtubular member having at least onev pin arranged in saidslot for resisting rotational movement of said second tubular member, said second tubular member being adapted to support-said source of ions,-a gear operatively connected tosaid second tubular member for moving said second tubular member along the axis of said ionpath, a pinionoperatively engaged with said gear,-and means projecting outside said vacuum pump housing for moving said pinion.

No references cited. 

1. ALIGNMENT APPARATUS FOR A SOURCE OF IONS WHICH COMPRISES, IN COMBINATION, A FIRST TUBULAR MEMBER ADAPTED TO PROJECT WITHIN A PRESSURE REDUCING MEANS TO DEFINE A PATH FOR SAID IONS IN FLUID COMMUNICATION WITH SAID PRESSURE REDUCING MEANS, SAID FIRST TUBULAR MEMBER BEING PROVIDED WITH AT LEAST ONE SLOT ADJACENT ITS FREE END IN SAID PRESSURE REDUCING MEANS, A SECOND TUBULAR MEMBER COAXIALLY ARRANGED IN SAID FIRST TUBULAR MEMBER FOR MOVE- 